package javaBase.nowcoder.HJ9_B_提取不重复的整数;

import java.util.Scanner;

public class Main {
    public static void main(String args[]) {
        Scanner sc = new Scanner(System.in);
        String s = sc.nextLine();
        sc.close();
        String temp = "";
        for (int i = s.length() - 1; i >= 0; i--) {
            if (temp.lastIndexOf(s.charAt(i)) == -1) {
                temp += s.charAt(i);
            }
        }
        System.out.println(temp);
    }
}
